1. Field
The following description relates to an endoscope apparatus and an image processing method of an endoscope apparatus, and more particularly, to an endoscope apparatus that provides narrow band imaging.
2. Description of the Related Art
An endoscope is a medical tool that may be inserted into a human body in order to provide observation of organs or a body cavity in which a lesion may not be directly observed without an operation or incision. An endoscope includes a narrow, long insertion portion for insertion into the human body to facilitate observation of organs in the body cavity. As image processing technology has developed, initially a black and white camera was used to capture an image of each part in the body cavity, and thus a lesion in each part may be examined in detail through a captured image. More recently, the simple black and white camera has been replaced by a high resolution color imaging device so that a lesion may be observed in more detail. Also, a chromo endoscope that captures an image after dying a surface of the body cavity with a particular pigment according to the type of a lesion to be identified has been used.
A narrow band imaging (NBI) endoscope has been suggested to improve lesion identification. The NBI endoscope is based on a principle that a depth of light penetrating tissue varies according to a wavelength of the light. For example, the NBI endoscope captures an image of each part in the body cavity using a blue, green, or red light of a narrow wavelength band, instead of only using a general white light of a wide wavelength band. Accordingly, an image of a surface, a middle part, or a deep part of a mucous membrane in the body cavity may be obtained according to a wavelength of the light in use. Thus, a lesion may be more easily identified according to differences among the obtained images. The NBI endoscope may be used to determine, for example, esophageal angiodysplasia or a stomach cancer in an early stage that does not protrude yet, tumor lesion of a large intestine, and loss of normal vessels.
As one example, the NBI endoscope separates a visible light of a wide band into blue, green, or red light of narrow bands using a rotary filter wheel. The separated narrow band light is sequentially or selectively illuminated onto a particular part of a body cavity to obtain an image.